The present invention relates to an actuating drive comprising two friction partners. A related actuating drive for a motor vehicle's window-lifting mechanism is disclosed in DE-U-89 03 714.
In electromotive window-lifting drives it is desirable to damp the abruptly braked driving torque when the upper or lower limit-stop point of the lifter mechanism is reached. To accomplish this result in the door of a motor vehicle, a rubber disc is installed as a damping liner between the worm gear wheel driven by the electromotor and the driven or slave disc connected to the output of the window lifter. This rubber disc allows a certain tangential compliance between the worm wheel and the slave disc when the limit-stop point is run up against. With a cup-shaped edge, the worm wheel overlaps the outer rim of the driven disc to such an extent that it can brace itself radially against this driven disc when the gearing forces of the worm shaft act on the worm wheel. When there is a simultaneous bracing action and relative movement between the worm wheel and the slave disc, undesirable squeaking noises can result.